I have a 15" Macbook Pro (2006) that the tech guys at OWC referred to as a 1,1 system. It has a 2 GHz duo core proc, 1.5 gig of dram, and a 100GB Seagate internal HD that just died. It was running 1.04.11 software (my original startup disks are 1.04.6)

After trying both drives externally and internally I experience the same problem. When only the new internal drive is used at startup, I get a grey screen with flashing apple symbol to grey circle with slash and occasional folder with question mark. When booted from the 1.04.6 OS install dvd, it reads the capacity of the internal drive wrong (as 5.5 TB) and will not let me do anything with it. When I boot from the external USB drive (identical as internal with same software) the system will boot from the external drive and now disk utility reads the correct capacity of the internal drive and lets me partition it. But the internal drive still will not show up in the startup drive utility as a choice to boot from. I was only able to install system software when the drive was external, never able to install on the internal drive (without making it external).

Here is what I have done so far.

I ordered 2 Western Digital 750GB drives (one with a diy case kit for external USB use). I froze the original HD for 3 hours and tried it again to no avail (grey screen, file folder with question mark). I replaced the internal HD with the new WD 750GB drive and booted from the apple 1.04.6 install disk. The drive utility function read the internal drive as a 5.5 TB drive and would not allow me to partition, initialize or otherwise touch the new drive. When I select partition, I get a dialog box that says the "Disk utility lost it's communication with the disk management tool and cannot continue. please quit and relaunch disk utility"

I zapped the nvram and reset the smc (twice each). Hardware test shows no problems when run from the installer dvd. The OWC guy asked me to install the OS on the external drive, which I did. It would then boot from the external USB drive (slow). After doing the software updates from the apple menu, I removed the external drive from the case and put it in as the internal drive. Now it has the same problem as before. It won't be recognized as a startup drive and is listed in disk utility as a 5.5 TB drive. I installed the OS on the new external dive, did updates, and as before, the MBP will boot from the external USB HD, and disk utility reads the internal disk correctly (698,XXX GB) and mounts the internal disk. I can copy data to the internal HD, but it still will not show up in the startup drive menu, or let me boot from it. It will not auto mount without the external drive as the boot drive. I was thinking bus or logic board, but if either of those were defective, I would expect disk utility to always read the internal HD incorrectly as 5.5TB, instead of reading it correctly only when booted from another drive. The same result happens with either o the new drives in either internal or external spots. The OWC guys are sure the drives are completely compatible.

I could sure use some help with this one!